This invention relates to auxiliary hoist controls. More particularly, the invention relates to an auxiliary hoist control and position load positioner which may be utilized to raise and lower large, bulky, or heavy objects over short distances and can accurately position the objects with respect to the vertical. More specifically, the invention discloses a Radio Frequency, remote controlled, load positioner heretofore unavailable in the prior art.
Precision load positioners and auxiliary hoist controls have been previously used in connection with hoists, such as a block and tackle, for the assemblage of heavy structures. An example of such a hoist control is illustrated in U.S. Pat. No. 2,500,459, issued to Hoover et al and assigned to Merrill et al. In such devices provision has been made for the control of hydraulic fluid in a piston cylinder arrangement connected to a load engaging means, whereby the load supported from the load engaging means is lowered by means of the by-passing of hydraulic fluid around the piston in the cylinder. Such devices failed to gain widespread acceptance as auxiliary hoist control devices.
Another auxiliary hoist control and precision load positioner was disclosed in U.S. Pat. Nos. 3,025,702 and 3,110,177, issued to Merrill et al and assigned to applicant herein. The Merrill patents provide positive control over the lowering and raising of extremely heavy loads supported by the control. However, since the raising and lowering mechanisms of the device were mechanically operated levers mounted on the hoist control device itself, it became apparent when lifting large, bulky or fragile loads that a need existed for a remotely controlled load positioner to be able to more conveniently control the precision load positioner when lifting very large, bulky or fragile bodies where access to the auxiliary hoist control is very difficult if not totally inaccessible.
It is conceived that loads of several hundred tons could be accurately positioned with the load positioner disclosed herein by increasing the size of the load positioner and by increasing the number of load positioners to distribute and support a relatively large, bulky or heavy load.
In the load positioner utilized in the Merrill prior art and in the present invention, a valve assembly provides for the controlled escape of that portion of the hydraulic fluid which supports the piston within the cylinder. The hydraulic fluid escapes through the valve assembly into an annular storage chamber. The storage chamber is divided into two portions by a separator ring. The lower portion of the storage chamber contains the escaped hydraulic fluid. The upper portion of the storage chamber is sealed from both they hydraulic fluid and the external atmosphere. Air or other compressible fluids are contained in the upper storage chamber. As the hydraulic fluid escapes from the cylinder into the lower storage chamber, the separator ring is forced upward so as to compress the fluid stored in the upper storage chamber. This compression of the fluid in the upper storage chamber provides a method of retaining the balance of pressures throughout the system and for returning the piston to its original, retracted position.
The valve assembly is of novel construction and also functions to permit the passage of hydraulic fluid so as to equalize the pressures within the cylinder and in the annular storage area when the load is removed. In other words, when the load is removed, the valve assembly, which previously acted to allow passage of fluid from the cylinder to the annular storage area, now functions automatically as a dump valve to allow passage of fluid from the annular storage area to the cylinder. This valve assembly is hereinafter referred to as the xe2x80x9cdown valve.xe2x80x9d
A pump is provided in the load positioner to furnish means for returning the piston to its retracted position when a load is engaged. The pump withdraws hydraulic fluid from the storage chamber and injects the fluid into the cylinder, thereby forcing the piston upward. This pump is hereinafter referred to as the xe2x80x9cup pump.xe2x80x9d
The present invention fully incorporates and improves on the foregoing Merrill art, also owned by applicant, and in doing so solves a long standing need by disclosing a Radio Frequency (RF), remote control capability for an auxiliary hoist control precision load positioner that is necessary for fragile or expensive loads that are also large or bulky loads and that are difficult if not impossible to monitor in moving or in performing an assembly.
The invention is an RF remote control auxiliary hoist control precision load positioning device and system. A transceiver controller unit is attached to an existing precision load positioner and is coupled by RF means to a transceiver hand control unit in the hands of an operator a safe distance away from the load and the load positioner, as well as the supporting crane. On power up, the dual transceivers are set in constant two way communication with each other with redundant circuits and an Emergency Stop override button for xe2x80x9cfail safexe2x80x9d requirements. The system software and firmware is set up to run an automated calibration and self check on power up and enables operator through various Menus and Screen Displays to control or to change default functions for various variables of interest such as Load Linear Travel, Load Deviation, Load Weight, Command Verification. Various buttons on the Hand Control Unit allow the operator to program the system by remote means, and load lifting and lowering is commanded by simple two way movement of a Joystick on the Hand Unit. By such means an operator can raise and lower a very heavy, bulky, fragile, or expensive load without incurring damage to the equipment being raised/lowered and without danger to the operator.
It is therefor a primary object of the invention to offer an auxiliary hoist control, precision load positioner system and means operable by remote means;
Another object is to provide a load positioning system that can be operable remotely without interference from dust, debris, intervening equipment or structures, or visibility day or night.
It is another object to provide for a remote control load positioner device and system operated by RF means.
Another object of the invention is to provide a redundant xe2x80x9cfail safexe2x80x9d load positioner with Emergency Stop override features.
Another object is to provide for an intelligent, microprocessor operated precision load positioning system.
Another object is to provide for an electromechanically operated load positioner system.
Another object is to provide for a programmable load positioning system that can be automated to limit human involvement.